1. Field of the Invention
The present invention relates to technology for processing a moving image.
2. Description of the Related Art
With the advancement of image capturing technology using digital cameras or the like and the current social trend, so-called monitor cameras have become widespread that capture a moving image with the purpose of monitoring or status confirmation, and record that moving image as digital data. Communication cameras employing the same technology have also become widespread. Such cameras are fixed in a location according to their purpose, and are often provided with a function for the camera to rotate according to a rotational axis, or to enlarge or reduce using a zoom function. Changes in the image capturing position (direction) of such cameras are ordinarily referred to as pan, tilt, zoom, or the like. By performing remotely-instructed operation of this pan/tilt/zoom function via a network or the like, a user can capture, record, and reference an image in a desired direction. On the other hand, with the increased capacity and reduced cost of storage devices, which usually are hard disks and memory cards, it has become possible to adequately record a moving image of a fixed length of time. There has also been a proliferation of various recording formats for moving images by MPEG (the Moving Picture Expert Group) and various manufacturers. One characteristic of recording formats that have recently come into widespread use is that image data (hereinafter, referred to as an “image frame”) captured in time-series at a particular instant in time is not simply recorded in order. That is, it has become possible to record, in addition to image frames, information for grouping those image frames and reproduction time (timestamp) information for individual frames, or image capturing time, image capturing parameters, and the like for the whole of the moving image, as metadata. Examples of typical recording formats include formats such as QuickTime (registered trademark) format and a format generally called MP4. Such recording formats have comparatively flexible extendibility. For example, with such formats it is possible to also store copyrighted information that changes in time-series along the time axis of the moving image, information about the image capturing apparatus of the whole of the moving image, or the like.
For example, in a monitor application or the like, in particular, technology is necessary for extracting or selecting a specific region in time or space from a moving image that has been captured. This is because there are often cases in which it is necessary to selectively perceive a target portion with various conditions, such as when there is a change in the image from the ordinary state. From such a background, conventionally, schemes have been put into practical use in which, with the object of monitoring, when movement is detected in an image frame, a marker is added to the moving image that is captured and recorded. Specifically, a function has been put into practical use in which, in a format in which each image frame or a group constituted from a plurality of image frames is specified, a flag that indicates abnormality is established, and when reproduction is performed, this flag is referenced and only the frames with this flag are emphasized.
Alternatively, schemes have been put into practical use in which, by operating a pointer input apparatus such as a mouse while referring to the image captured and recorded, image information such as a rectangle is clearly overwritten and recorded on an image frame whose recording is complete or a plurality of image frames including the previous and subsequent image frames.
Further, technology is known in which by adopting technology to extract a specific region from the captured image, a specific region is extracted from the moving image by extracting a human being or a moving car. Also, technology is known in which by adopting the above technology, the pan/tilt/zoom function is operated based on the position and size within the captured range of the specific region that has been extracted (for example, see Japanese Patent Laid-Open No. 2002-262138).
In the prior art, when a specific region in space is selected from a moving image that has been recorded or a moving image that will attempt to be captured and recorded, and the selected region is stored associated with moving image data across the entire moving image, there are the problems described below.
In the case of Japanese Patent Laid-Open No. 2002-262138, based on a specific region of an image that has been recorded or is being recorded, it is possible to operate the camera independent of this image. However, it is a problem to retroactively select a specific region in space from a moving image and record it associated with an image that has been recorded in the past.
The present invention was made in consideration of the problems in the prior art described above, and it is an object thereof to provide technology that allows a specific region in space to be associated based on individual image frames of a moving image and position information such as the direction and angle of view when those image frames were captured.